


A Demon's Burning Heat

by FamousFox13, kingkjdragon



Category: Ao no Exorcist | Blue Exorcist
Genre: Body Modification, Body Worship, Cock & Ball Torture, Cock Slapping, Cock Warming, Cum Addiction, Cum Inflation, Fisting, M/M, Masochism, Master/Slave, Mind Break, Multi, Pegging, Piss Addiction, Piss Inflation, Sadistic Rin, Size Humiliation, Spanking, ball busting, personality change
Language: English
Status: Completed
Published: 2019-07-13
Updated: 2019-07-13
Packaged: 2020-06-27 18:24:56
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,693
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19796512
Author URL: https://archiveofourown.org/users/FamousFox13/pseuds/FamousFox13, https://archiveofourown.org/users/kingkjdragon/pseuds/kingkjdragon
Summary: When Rin is hit with a form of Demonic Puberty he is bed ridden and has to be kept away from everyone, too bad no one told Shima.





	A Demon's Burning Heat

**Author's Note:**

> We do not won Blue Exorcist

For one Rin Okumara, the past few weeks have been an absolute hell. For the past week or two, he had been feeling well annoyed, pissed off, and not to mention all around like he was just willing to go off on the next person to piss him off. He had been feeling like he was burning up, like no matter what he did he couldn’t stay cool, in class he moved to sit by the window, or under the air conditioner, he would strip off his jacket, his shoes and socks, and if he was bold enough forgo wearing pants and just shred them to turn them into shorts to wear hoping that it would help get rid of the heat. Suffice to say, it didn’t help, it didn’t help him at all.

Another thing, was that along with his moments of rage, and his moments of heat he’d feel incredibly, unimaginably, horny. He found that he couldn’t control himself, one moment he’d be fine-aside from the heat and his anger-to being hard and hot and bothered as hell. He’d tried jerking off in his free time, but that didn’t do anything heck it only seemed to make it even worse than before. He had even tried using some toys-that he may or may not have bought-to try and get off but again like when jerking off he found himself unsatisfied and it drove him crazy!

Finally, after he had almost sent Bon into-no through a wall- his brother Yukio had dragged him to see Sir Pheles in hopes of getting some answers out of their demon principle. Upon arriving, he gave them the usual song and dance, giving half truths and leading them on. Finally, when Rin sliced his desk in half, resulting in both halves being burned to ashes did the man give them a straight answer. The reason behind Rin’s outburst, and his fits of arousal was simple. 

Puberty, Rin was going through a Demons version of Puberty. Of course, both brothers had been shocked, but Rin was more horrified then shocked. To think, he was going to have to go through puberty not once but twice. Of course, Mephisto told them the “harmless” issues that would come with Rin dealing with a demon puberty. Almost right away, Yukio a fit about the fact that Mephisto hadn’t told them about this before hand, and every annoying headmaster had one thing to say.

“You didn’t ask.” He said, giving them his ever present coy grin. A grin, that nearly made Rin unleash his flames and attack him. After restraining Rin, Yukio had managed to coax the full answers out of Mephisto and asked what he should do. The answer was simple, lock Rin up in his room and keep him contained until his puberty was over, meaning Rin would have to stay away from his female classmates and be locked in his room. Rin wanted to argue, but by then Yukio had agreed and had then dragged him to his room, with plans to take care of him until his puberty was over. 

Which is where we are at our current predicament. 

“WHAT DO YOU MEAN YOUR LEAVING?!” Rin roared, literally roared causing the entire room to shake. “HOW CAN YOU BE LEAVING AT A TIME LIKE THIS?!” 

“I have an important Mission, Shima will keep you company and Bon is allowed to come over, I even got the school to splurge and buy some new game system and flat screen for the Rec room,” Yukio said as he packed his bag.

“S-Shima?!” Rin choked on his own breath. Of all people, his brother had to pick Shima. “Why him?! Why not someone else?! I mean just-why him?!” 

“He was the only one willing to do it and no females are allowed near you,” Yukio said as he picked his bag up and moved towards the door sliding a key into it to open his destination.

“B-But...but.” Rin couldn’t think of anything to say, he had nothing against Shima nothing at all. But, it was the fact that he had a small slight issue-read crush-with the perverted male. He couldn’t help himself, something about him was just so attractive, and alluring and just-Rin blushed as he suddenly felt his cock throb in his pants and felt another flame of arousal go through his body.

“No buts he will be here this evening and remember the guards will shoot if you try to leave the dorm,” Yukio said leaving Rin alone.

Long after Yukio left, Rin had torn off his clothes to try and ease his heat. But, even as he sat naked as the day he was born in his room it wasn’t helping. His tail, was waving around as he was sweating and panting like he was in the middle of a desert, his entire body drenched in sweat and drenching his bed as his musk filled the room bathing it in his scent/musk. As he laid around, he was completely unaware of what was happening to him as his puberty ran its course. For one, his once untrimmed nails grew longer and sharper as he flexed his hand and his nails unsheathed like that of claws of a feline, as the pupils of his eyes narrowed becoming slit like that of a reptile. 

Muscle upon muscle grew - pecs becoming full. Biceps becoming so large they could beat a professional bodybuilder at full size, and the perfectly chiseled ass somehow becoming even more bubbly and shapely. His balls even started to grow, becoming bigger and fuller filling with more cum then they could ever produce before, not to mention his cock it was growing getting longer, thicker, bigger growing just as his balls did. 

A few hours later the front door opened and a voice echoed through the dorm, “Hey Rin where are you.”

Rin could barely hear him, his entire world was nothing more than an unrelenting burning heat. His cock, hard as a fucking rock dripping-oozing with pre that spilled down all over his pecs and newly formed abs. His new cock, was now 20-inches long as thick as his calf, covered with blunt spikes as his basketball size balls swelled and churned with cum making him groan as he reached down with both hands and began to pump his cock.

“Rin where are you,” Shima called even louder and kept on repeating waiting for an answer.

“S-Shima.” Rin groaned, his eyes filled with lust as he slowly pumped his cock panting and gasping as another wave of heat swept through his body causing him to sweat even more and release more musk into the air. “Fuck..S-Shima!” he called, his lust filled mind wanting one thing and one thing alone and that was Shima.

“Where are you?” Shima called even louder as he started up the stairs.

Rin groaned, as he managed to lift himself up. Slowly, making his way out of the room as he continued to grunt and groan as he walked through the halls. “Shima.” Groaned Rin, as his musk began to fill the hall sweeping through it and covering the hall and the rest of the halls connected to it. “Shima.” He growled, as he could smell the male and started to move even faster. 

Shima kept moving looking for Rin. “Rin! Rin! Come on dude! If this is your attempt at playing a prank it's not funny.” He looked through the numerous empty rooms, and would have to admit he was a bit nervous being here alone with Rin, there was something in the air, something that was making the hairs on the back of his neck stand up and making him wish he had brought his staff with him. 

Rin was able to locate Shima, thanks to his newly enhanced senses. He got closer, and closer to him his scent growing stronger and stronger as he got closer to him. “Shima, Shima, Shima.” He repeated over and over again, as he was getting closer to him his cock leaking a trail of pre all over the floor.

Turning Shima froze at the sight of Rin’s new form his eyes going to the massive leaking cock and rippling muscles that all moved like fluid. “R-Rin?” He gulped, taking in the massive muscled form of his classmate before him. “U-Uh, you been hitting the gym with Bon?” He joked, as he didn’t like the look in the teens eyes or his eyes in general as he started backing up slowly. 

“Shima.” Purred Rin, his eyes hungrily eyeing the male as he his now longer tongue snaked out and licked his lips. “MINE.” He roared, dashing towards Shima using his newly gained claws to completely rip apart his clothing. 

Shima yelped as his thin toned body was revealed and the fact his hair was not the only pink thing on his body his nipples were bright pink and the head of his soft cock was just as pink but he was completely hairless.

Purring in joy, Rin’s tail wagged as he reached out and grabbed Shima by his hair. Roughly pulling the other boy down towards his now soft but still leaking cock, with his other hand he forced the boy’s jaw open and shoved the thick bulbous head of his cock into the boys mouth. Moaning in bliss, feeling the warm wet heat around the head as his entire body shuddered, and much to Shima’s shock, horror, and disgust Rin started pissing into his mouth.

Shima groaned trying to fight back his fist pounding on muscled thigh. As he tried to pull back but was forced to swallow the piss not knowing his body was already becoming addicted to the demonic piss. ‘ _ No no no! Stop this! Rin come on stop! You’ve got to stop this! I don't want this I don't make it stop! Someone make it stop!’ _

Rin on the other hand was groaning, panting as he pushed the other boy’s head into his crotch forcing his nose right against his pubes. As his face was smashed against the pubes Shima got a nose full of Rin’s newly demonic musk, and it was strong, some what earthly, and yet it had a different kind of scent to it something that was both otherworldly and yet at the same time it was also alluring, so manly, just so..so addictive. 

Slowly Shima’s struggles faded as he breathed in the musk his head spinning as he tried to understand what is going on, ‘ _ I don’t know what to do, but this is starting to feel right, _ ’ he thought his head light from the musk and lack of oxygen.

Rin’s stream of hot piss didn’t stop, and as it continued neither one of them were aware of the fact that Shima’s body was changing just like Rin’s hand. First, all the hair on his body began to burn off until the only hair on his body was the hair on his head and his eyebrows leaving his entire body smooth as a babies bottom, secondly his entire body structure changed as his once lanky body changed into one of that of a fit swimmer. Another thing, was that his ass had grown it was bigger rounder, fuller and more bubble like and bouncy. Finally, Shima felt his entire body felt sensitive, no it wasn’t just sensitive it was burning it was hot burning up like he was on fire. His insides start heating up and itch like crazy craving something, something big, something hard, and that thing was currently in his throat.

Shima groaned forcing his mouth to sink further down the massive shaft as it started to harden in his throat. The dark hair tickling his nose as he moaned around the cock filling his throat.

Feeling Shima sink down on his cock, Rin groaned as he reached down and fisted his hair as he started fucking his mouth, his balls slapping against the boy’s chin over and over again loud echoing smack’s filling the room as they bounced off the walls. “Fuck Shima.” Moaned the massive muscled teen, as he gave a feral grin his newly grown fangs flashing in the light. “Fuck, you’re mouth feels so good so fucking good.” Thick globs of pre were squirting from Rin’s cock and shooting right into the male’s mouth.

Moaning Shima brought his hands up to rub the massive orbs hanging from Rin’s crotch his hands running over the tight skin of the huge sack.

Rin let out a loud purr like noise, as he continued to slam into the pink haired male. His musk only growing stronger, the more he began to sweat and the more he began to fuck the pink haired male’s mouth, thicker globs of pre spilling into his mouth as Rin felt himself growing closer and closer to his climax. A string of curses, slipping past his lips as he started humping the boy’s face driving his cock in and out of his throat.

Working his throat Shima tried to make Rin cum as fast as he could, the desire to taste the cum building.

Rin couldn’t hold back, pushing Shima’s face into his crotch Rin came right down his throat and into his stomach. Wave after wave, of thick warm demonic cum poured right down Shima’s throat and into his stomach, before Rin pulled back and letting Shima get a taste of his cum as it filled his mouth. Once he was finished, he pulled back letting the last bits spray Shima across his face and in his hair. Looking at Shima, covered in his cum and panting and mewling Rin wanted more and he knew what he wanted. “Show me your ass, I want to see it now.”

Shima moaned, as he looked at Rin’s drool covered cock, watching as it waved back and forth almost hypnotically. He couldn't take his eyes off of it. He bit his lip, slowly turning around as all he could think about was having that big, thick, cock inside of him. “R..Rin, p-please.” He moaned hotly, his cheeks tinged a reddish pink as he gave his ass a shake smiling as he watched Rin watch his ass bounce up and down and from side to side. “I-I need you, please! I need-no I want you to fuck me! Please! Fuck me Rin!”’ 

Rin effortlessly pinned Shima down, his ass up in the air as he rubbed and grounded his cock against this ass. “You’re asking for it Shima.” Growled Rin, thought he was grinning. “You’re asking me? To take your V-card, asking for my massive cock to give you what you so desperately deserve.” he gave a harsh grind against him. “Is that what you’re asking me?”

“Yes please I need it,” Moaned Shima pushing back on the massive cock his hole twitching like it was kissing the beast of a cock.

Rin growled, rubbing the swollen tip against Shima’s twitching hole. “You asked for this.” He growled, never losing his smirk. “Remember that~” He chuckled, as without another word the fat head of his cock slid past the wet glistening hole and into Shima’s ass. Their moans mixed in a soft harmony of lust and desire as Shima’s back arched. Inch after Inch slid into him as Rin groaned feeling Shima’s walls stretch only to quickly squeeze back around his cock. His hands, caressed and gripped Shima’s ass and hips and with a small jerk of his hips he buried the last few inches inside of Shima’s ass.

Howling Shima felt his mind break as he became consumed by the massive cock in his body, addicted to the feel of it fucking him with no mercy.

Every thrust thrust, came with a low growl that had Shima melt as he was completely at Rin’s will. With each thrust, the dull studs on his cock rubbed and grinded against Shima’s inner walls making him howl and scream in pleasure. Tears spilled over Shima’s eyes as he could only gasp, and moan only to yelp as Rin flipped him on to his back so he was looking down at Shimas face as he pounded away at him, the new position having Rin’s cock stab right at the pink haired male’s sweet spot making him scream even more throwing his arms around Rin’s neck, his mouth parted in a permanent cry of pleasure.

Screaming in pleasure Shima felt his cock pulse as it bounced with each thrust spurting cum over his and Rin’s bodies.

Rin couldn’t help it, seeing Shima cum was the push over the edge that he needed. He let out a roar that tore through the entire building, as he jammed his cock into Shima’s prostate, as at the base of his cock there formed a knot the size of a baseball it slammed against Shima’s ass as he tried his hardest to get it inside of him. The rough thrust, the spines rubbing against his inner walls, and the knot slamming against his ass were driving Shima into a state of pure never ending bliss as finally Rin shoved his knot into Shima’s ass. 

His knot expanded inside of him locking them together, as his balls pulsed and throbbed against Shima’s ass pushing out load after load of his thick hot cum. Wave after wave of cum flooded Shima’s ass as heat ran through Shima’s body as the surge of cum that Rin was dumping into him had him writhing and moaning against the larger male as his body took every last drop of his seed, but the sheer amount of Rin’s seed not to mention the fact that his demonic puberty had him pushing out even more and he could only watch in utter joy as Shima’s stomach soon began to bulge and then it started to grow expanding getting bigger and bigger as Rin filled him up making the pink haired male look as if he was knocked up. Unseen by either of them, there was a glow that came from Shima’s pelvis as the pink haired male was toto drunk on pleasure to notice as he gained a strange runic looking seal that looked to be demonic and yet arcane at the same time. 

**Scene Skip**

It had been hours, days, or maybe it had been weeks the two of them didn’t know. Rin and Shiima had spent that time fucking, on every solid surface there was in the building and seeing as how there were so many empty rooms they had plenty of space and room for them to fuck as Rin’s demonic puberty ran its course sending the two of the into a nearly endless spiral of lust and desire. They fucked in so many places, in so many positions that if someone had seen them they would have called the two inhuman for the ways they had fucked. And with each coupling, Shima’s stomach only got bigger and bigger as Rin pumped him full and made sure that every last bit of his cum stayed inside of him and wouldn’t escape, his new instincts telling him to look after his now heavily pregnant mate. They were finally resting, laying on a bed in one of the rooms Shima had his hands on his stomach cooing softly at it as he could only imagine the number of children he was going to have and what they would look like. That thought alone, had him cooing at his stomach even more.

The front door opened as another male entered groaning under his breath “Why do I have to check on these idiots they probably sleeping like morons,” this was Shima’s friend Bon.

Rin’s new sensitive hearing was able to hear him. A part of him, had always wanted to put Bon in his place, with how uptight, and how much of a pain of an ass he was to him he decided to finally do something about him and that something was make him pay for it. “Oh this.” Rin purred, as his scent was already beginning to fill the room once more, he could see it was having an effect on Shima who was whimpering and moaning as he felt his body tingle from inhaling his mate’s scent. “This, is gonna be good.” he chuckled as he opened the room door “Bon!” He yelled, his voice traveling down through the hall. “We're here!” 

Following the call Bon headed to a room with an open door and froze at the sight he saw. “What the hell!” Bon screamed, unable to look away.

What Bon saw was something he never wanted to see, Rin fucking Okumara on his back arms resting behind his head, as he laid with his legs spread a grin on his face as he watched a very plump looking Shima bounce up and down on his massive cock like his life depended on it. The poor pink haired boy, had a dopey grin on his face, tongue hanging out his mouth and a line of drool dribbling down his chin while his own cock bounced around slinging strands of pre around that splattered against Rin’s new body. “Oh.” Rin said, as if Shima was currently riding him like a bucking bronco. “Hey Bon, what’s up?” 

“You fucking Fag what the hell are you doing,” Bon screamed glaring at Rin.

“Me? I’m just sitting here relaxing.” Smiled Rin, showing off his fangs. “It’s Shima who’s doing all the work, I mean look at him.” Shima had his head thrown back, his eyes were half lidded as he rolled his hips bouncing harder and faster, he was a boy on a mission and that mission was to get more cum out of Rin’s monster of a cock, he wanted to be filled more, to have all of his cum inside of him and to be knocked up with even more kids. “It’s Shima who’s taking my cock like a pro.” Rin’s tail came up and smacked Shima’s ass smirking as he watched Bon’s eyes move as Shima’s bubble butt bounced up and down. 

Bon growled, as he tore his eyes away from looking at Shima’s round, bouncing, bodacious, bubble butt. “You have to be kidding!” Snarled the dual haired teen. “There is no way Shima of all people would do this! You had to be the one to do this! You and your fucking perverted nasty ass disgusting contagious faggot dissease!” He yelled. “I don't care how you do it, I don't’ care what it fucking takes! Fix what you did to him right now you-” Bon was stopped as he was suddenly frozen in place.

Rin had planned on playing with Bon, to mess with his mind and play with him before taking him. But now, he had pissed him off, Rin had stopped Shima from bouncing on his cock and pulled him off it making him whine from the suddenly feeling of emptiness. Standing tall, Rin stalked towards Bon who was frozen and unable to move, or even speak due to Rin’s currently overbearing power and musk that was coming off him in waves. “You know.” He said lowly. “I was gonna be nice, and simply play with you.” Like a viper, Rin’s tail shot out and grasped Bon around his neck. “But, I think a little punishment is in order.”

Gasping Bon tried to reach for something to force Rin back while pulling on the tail wrapped around his neck.

With nothing but his tail, Rin forced Bon on to his hands and knees. “First off these have to go.” He said as with his claws he completely tore Bon’s clothing to shreds letting the ripped clothing fall to the ground. “That’s better.”

Bon glared trying to stand up even though he was naked and at the mercy of a demon. Bon, unlike Shima was built a lot better than him, giving him what could only be described as a twunkish body. He was built, with muscles that were compact, a solid set of four pack abs toned arms and legs and a firm toned ass. 

Rin smiled, as he then sat down on Bon’s back. “You are going to be punished Bon.” He could feel him wiggling and shaking trying to get free. “So take your punishment like a man!” He raised his hand and brought it down hard across Bon’s ass with a loud echoing smack. “You’ve been a pain in my ass for far too long.” Another smack, followed by another and another. “And now, it's time your ass took the brunt of it!” 

Biting his tongue Bon refused to make a sound as he was assaulted by Rin, even as his head started to spin and his hole twitched.

Blows rain down, one after another, an endless assault on the dual haired teens ass as Rin watched his cheeks slowly turn from their usual color to a bright pink that was slowly darkening to a shade of red. “You can try and stop it, but it won’t do you any good.” He growled, as he released the grip his tail had on Bon’s neck but with Rin’s weight pinning him down he was unable to move, and unable to prevent Rin’s tail from snaking down towards his balls and wrapping around them and giving one harsh tug yanking them away from his body and making them stretch ever so painfully and even as Bon started shaking Rin just spanked him harder.

Finally, when Bon’s ass was nice and as red as a cherry, Rin moved pining Bon to the ground with his ass up in the air. “Normally, I’d prep you but you’re a special case.” He smiled before slamming his massive cock right into Bon’s ass the spikes raking along his inner walls as he didn’t stop until he was balls deep inside of Bon. “Sweet fucking shit~” Groaned Rin, as he waisted no time and began thrusting into his ass pounding away at the boy’s no longer virgin hole. “I knew you’d be a tight ass, but fucking hell! I didn’t think you were a literal tight ass!”

Bon screamed as his cherry was shattered with no mercy and pain flooded his system making his head fall forward where he saw his own cock was rock hard.

“I can smell it Bon.” Smirked Rin, leaning down and bit down on the shell of his ear. “I can smell that you’re enjoying this, that you’re enjoying me fucking your ass, having my cock tear your cheery apart and turn your ass into my own private little hole to fuck.” His thrust got harder and faster, his massive nuts spanking his ass turning it a deeper shade of red. Sweat mixed with groans, grunts, and growls as Bon was soon reduced to a gasping mewling moaning mess, his entire body singing in pain and pleasure that mixed together in a form of ecstasy that had caused the teen’s mind to sink into an abyss of pleasure and rapture. It only increased, when he felt the knot smack against his hole as Rin’s balls started to draw upwards showing just how close he was to blowing his load.

The sound of a cocking gun came from the door to the room. “Stop now or I will shoot,” Came Yukio’s voice the gun aimed at Rin’s heart.

Rin did stop, only after he slammed his knot into Bon’s ass forcing his inner walls apart as the knot swelled locking the two of them together as burst after burst of Rin’s thick seed erupted inside of his body in a steady stream. “Oh come on Yuki~” Rin looked at him over his shoulder, his eyes gleaming as there was a sudden flash and a tongue of blue colored flames shot towards his brother who was too slow to dodge them and his clothes were signed off his body while his gun was melted into a puddle of slag. “No need to be so hostile.” His tail moved, snaking out and wrapping around Yukio’s neck and pulling him close to his brother. “It’s just a little fun~”


End file.
